1. Field of the Art
This invention relates to a method of conducting chemical plating selectively on a specific position or portion of a formed article consisting essentially of a polyarylenesulfide (hereinafter referred to as PAS) or a composition thereof. In other words, this invention relates to a method of producing a PAS formed article treated with selective chemical plating.
2. Description of the Prior Art
Recently, PAS or PAS compositions reinforced with fibers and the like have attracted much attention as a new engineering plastic material having excellent heat resistance, chemical resistance, nonflammability, mechanical properties and electrical properties. An attempt to use the PAS or PAS compositions as a substrate for printed wiring board has been disclosed in Japanese Laid-Open Patent Publication Nos. 96588/1982 and 3991/1984, etc.
Generally, to produce a printed circuit on a plastic substrate, so-called subtractive methods or additive methods have been used. Because of fewer process steps, suitability for high density wiring, etc., circuit-forming techniques according to an additive method utilizing chemical plating have been popularly used.
In such additive methods, those portions of a PAS formed article which should not be plated are preliminarily masked with an adhesive ink, a masking ink or the like, and then the masked article is subjected to chemical plating. Therefore, the methods have problems in that the adhesive ink, the masking ink or the like used for the masking must have sufficient durability against the severe conditions of the subsequent production steps. Thus, it has been desired to develop a technique which can form precise circuit patterns by means of selective chemical plating without using such a masking ink or adhesive ink.
On the other hand, as an additive method which directly forms circuit patterns, a so-called PD-R method, photo-form method and others have been known. All of these methods are positive type circuit pattern-forming methods in which only the parts irradiated with light can be plated. Thus, these methods are disadvantageous in that plating of the through-hole parts may be difficult.
It is desirable, not only from the viewpoint of printed wiring but also in view of the various uses of PAS formed articles, because of their excellent properties, to provide a method of applying selective chemical plating onto PAS formed articles.